Head-mounted image video display

ABSTRACT

A one-eye viewing type head-mounted image display device ( 1 ) that is compact and comfortably wearable consists mainly of a viewer ( 2 ) and an elastic member ( 38 ). The viewer includes an LCD ( 13 ), a main prism ( 32 ), a see-through prism ( 33 ), a frame ( 10 ), and a microphone ( 18 ). The main prism conducts an image, which is displayed on the LCD, to make the image viewable with either the user&#39;s right eye or left eye. The see-through prism is bonded to the main prism, transmits extraneously light, and conducts the light to a users eye. The frame bears the LCD at a predetermined position relative to the prisms. The microphone is mounted in the frame. The elastic member includes a nose rest ( 38   a ) which supports the viewer so that the viewer will be located at a predetermined position in front of the user&#39;s eye.

TECHNICAL FIELD

The present invention relates to a head-mounted image display device, ormore particularly, a head-mounted image display device for use inviewing an image displayed on an image display element.

BACKGROUND ART

In recent years, various types of head-mounted image display deviceshave been proposed to enable a user to readily enjoy a large-size image.The present inventor has commercialized a head-mounted image displaydevice that employs a free-form surface prism so as to be lightweightand offer high image quality.

The head-mounted image display device is connected to an image source,for example, a television, a video player, or a DVD player, thusreceiving a video signal or an audio signal from the image source. AnLCD and an optical system incorporated in the head-mounted image displaydevice projects an image on user's eyes. Moreover, earphones that are anaccessory are used to radiate sounds to the user's ears.

Various head-mounted image display devices have been proposed to beadopted as a display device that is used with, for example, a personalcomputer, a word processor, or any other office automation equipment andthat displays images.

Furthermore, the head-mounted image display device falls into a type ofdisplaying an image on user's eyes and a type of displaying an image oneither of the user's right or left eye. Various proposals have been madefor the latter type of displaying an image on one of user's eyes.

For example, Japanese Patent Unexamined Publication No. 4-58212describes a display for office automation (OA) equipment. The displayconsists mainly of an image projector, a light path deflecting member,and a head-mounted member. The light path deflecting member ispositioned to conduct light, with which an image is displayed and whichis emitted from the image projector, in a predetermined direction. Thehead-mounted member bears the image projector and light path deflectingmember. The image projector consists mainly of an optical image displaymeans and an optical member. The optical image display means has adisplay surface on which an image is displayed according to an outputsignal of a main unit of the OA equipment. The optical member projectslight, with which an image is displayed and which is emitted from thedisplay surface, to the light path deflecting member. The display isdesigned to maintain a proper distance between the eye and a displayimage.

Moreover, Japanese Patent Unexamined Publication No. 10-74051 describesa head-mounted display device having an image display means and aholding means. The holding means can be worn on an observer's head whileholding the image display means. The head-mounted display deviceintroduces light; with which an image is displayed and which is emittedfrom the image display means, to one of the observer's eyes. The holdingmeans can hold the image display means while being worn on either theright region of the head or the left region thereof.

Japanese Patent Unexamined Publication No. 10-123455 describes ahead-mounted display device having an image display means and a holdingmeans that holds the image display means and can be worn on anobserver's head. The image display means includes a means for emittinglight, with which an image is displayed, to a point in front of anobserver, an arm that is extended forwards from one side of theobserver, and an optical element attached to the front end of the arm.The head-mounted display device uses the optical element to change thelight path of the light, with which an image is displayed, and thusintroduces the light to the observer's eye. The optical element iscoupled to the arm so that it can be displaced in order to escape fromextraneous force that works on the optical element from forward.

Japanese Patent Unexamined Publication No. 10-75408 describes ahead-mounted display device having an image display means and a holdingmeans that holds the image display means and that can be worn on anobserver's head. The holding means includes a supporting member and atleast four pad members that are coupled to the supporting member. Thesupporting member can be elastically deformed so that the pad memberscan apply elastic force to back and front parts on the right region ofthe observer's head and back and front parts on the left region thereof,and can thus press the back and front parts.

Japanese Patent Unexamined Publication No. 10-39784 describes ahead-mounted display device having a means for emitting light with whichan image is displayed, a light path changing means, and a holding means.The light path changing means is located in front of an observer. Theholding means holds the means for emitting light with which an image isdisplayed and the light path changing means and can be worn on theobserver's head. The light path changing means can change the light pathof the light with which an image is displayed so that a virtual image ofan object of observation will be formed in front of the observer. Themeans for emitting the light with which an image is displayed and thelight path changing means are coupled to the holding means so that theycan be moved together over the spherical surface of the holding means.The center of the spherical surface is aligned with a position that iscloser to the observer than to the light path changing means.

Japanese Patent Unexamined Publication No. 8-305298 describes ahead-mounted display device that is worn on an observer's head and thathas an image display unit and a head-mounted holder which holds thedisplay unit. When the head-mounted display device is worn on anobserver's head, if the observer's line of sight is aligned with a frontdirection, an image is displayed outside a field-of-view range on thedisplay unit. If the observer's line of sight is aligned with anydirection other than the front direction, an image is displayed withinthe field-of-view range on the display unit. If the observer's line ofsight is aligned with the front direction, the components of thehead-mounted display device are brought to substantially outside thefield-of-view range.

Japanese Patent Unexamined Publication No. 8-320453 describes a displaydevice that is worn by an observer and has an image display unit and aholder for holding the display unit. An image-displayed position can bechanged within an observer's discernible range.

In recent years, personal computers that enable a user to entersentences or operation commands by voice have been put on the market.For example, a user wears a microphone-inclusive headphone or the likeon the user's head so as to enter voice.

The microphone-inclusive headphone has right and left headphones linkedby, for example, a headband. An arm is extended from the side surface ofone of the headphones, and a microphone is fixed to the distal end ofthe arm.

The foregoing microphone-inclusive headphone has the a microphonethereof located in front of the user's mouth using the arm thereof. Thearm therefore extends in front of the user's face. Since the headphoneis large in size, the headphone may be hard to handle or may be wornuncomfortably. The adaptation of the structure, which has the microphoneattached to the arm, to a head-mounted image display device as it iscannot always be said to be the best.

Moreover, a viewer that displays an image and projects it on a user'seye must maintain a predetermined positional relationship relative tothe eye despite a little movement of the head. If the positionalrelationship is maintained insufficiently, an image to be observed mayfluctuate or a distance from an eye may change. This causes a user tofeel uncomfortable. A technology for reliably bearing the viewerrelative to the eye is therefore needed.

Accordingly, an object of the present invention is to provide ahead-mounted image display device that is compact and can be worncomfortably.

DISCLOSURE OF INVENTION

According to a first aspect of the present invention, there is provideda head-mounted image display device having a viewer located in front ofa user's eye so as to make an image viewable. The viewer includes animage display element, an optical system, and a frame member. Theoptical system conducts an image, which is displayed on the imagedisplay element, so that the image can be viewed. The frame member bearsthe image display element at a predetermined position relative to theoptical system. The head-mounted image display device has a microphone,which converts voice into an electric signal, mounted on the framemember.

According to a second aspect of the present invention, the head-mountedimage display device in accordance with the first aspect may be disposedopposite the user's right eye so that an image displayed on the viewercan be viewed with the right eye or may be disposed opposite the user'sleft eye so that the image can be viewed with the left eye. Themicrophone is mounted on the frame member so that depending on whetherthe head-mounted image display device is disposed opposite the user'sright eye or left eye, the microphone will be located at either ofsubstantially symmetric positions on the user's head and will beseparated from the user's mouth by substantially the same distance.

According to a third aspect of the present invention, there is provideda head-mounted image display device having a viewer located in front ofa user's eye so as to make an image viewable. The viewer includes animage display element, an optical system that conducts an image, whichis displayed on the image display element, so that the image can beviewed, and a frame member that bears the image display element at apredetermined position relative to the optical system. The head-mountedimage display device further includes a supporting member that contactsa user's face to support the viewer so that the viewer will have apredetermined positional relationship to the user's eye.

According to a fourth aspect of the present invention, in thehead-mounted image display device in accordance with the thirdinvention, the supporting member is made of an elastic material. This isintended that the, supporting member can alleviate pressure which occurswhen the supporting member contacts the user's face, and the supportingmember can elastically deform in conformity with the shape of a regionof the user's head which the supporting member contacts.

According to a fifth aspect of the present invention, in thehead-mounted-image display device in accordance with the fourth aspect,the supporting member is shaped to contact a region of a user's face inwhich a bone lies subcutaneously close to the skin.

According to a sixth aspect of the present invention, in thehead-mounted image display device in accordance with the fifth aspect,the supporting member is shaped to contact a region in which at leastone of the nasal bone, cheekbone, and superior ocular bone liessubcutaneously close to the skin.

According to a seventh aspect of the present invention, in thehead-mounted image display device in accordance with the fourth aspect,the supporting member is formed substantially covering along theperimeter of the viewer in order to block the gap between the viewer anda user's eye.

According to an eighth aspect of the present invention, in thehead-mounted image display device in accordance with the third aspect,the supporting member covers the optical system and has a portionthereof shaped not to interfere with viewing of an image or sceneryconducted by the optical system.

According to a ninth aspect of the present invention, there is provideda head-mounted image display device having a viewer located in front ofa user's eye so as to make an image viewable. The viewer includes animage display element, an optical system, and a frame member. Theoptical system conducts an image, which is displayed on the imagedisplay element, so that the image can be viewed. The frame member bearsthe image display element at a predetermined position relative to theoptical system. The head-mounted image display device further includesan electric circuit board for a display element, an illuminating member,an electric circuit board for illumination, and a connector. Theelectric circuit board for a display element has the image displayelement mounted thereon. The illuminating member illuminates the imagedisplay element. The electric circuit board for illumination has theilluminating member mounted thereon. The connector connects the electriccircuit board for a display element and the electric circuit board forillumination to each other so as to be able to disconnect the electriccircuit boards each other.

According to a tenth aspect of the present invention, in thehead-mounted image display device in accordance with the ninth aspect,the electric circuit board for illumination is held in the frame memberor an illuminating member-fixing member that is fixed in the framemember. The surface of a portion of the frame member or fixing memberthat holds the electric circuit board for illumination is formed as adiffusing/reflecting surface that homogenizes and reflects lightemanating from the illuminating member.

According to an eleventh aspect of the present invention, there isprovided a head-mounted image display device having a viewer located infront of a user's eye so as to make an image viewable. The viewerincludes an image display element, an optical system, and a framemember. The optical system conducts an image, which is displayed on theimage display element, so that the image can be viewed. The frame memberbears the image display element at a predetermined position relative tothe optical system. The frame member bears the image display element soas to at least substantially seal the image display element. Thus, theviewer is substantially sealed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a head-mounted image display devicein accordance with an embodiment of the present invention that is wornon the user's head;

FIG. 2 is a sectional plan view showing the structure of the wornhead-mounted image display device in accordance with the embodiment;

FIG. 3 and FIG. 4 are a plan view and a partial side view showingadjustment that is performed using position adjusting mechanismsincluded in the head-mounted image display device in accordance with theembodiment;

FIG. 5 shows an image displayed while being superimposed on an image,which is represented by extraneous light, by the head-mounted imagedisplay device in accordance with the embodiment;

FIG. 6 is a partly enlarged sectional plan view showing the structure ofa viewer included in the head-mounted image display device in accordancewith the embodiment;

FIG. 7 is a partly enlarged longitudinal sectional view showing an LCDframe included in the head-mounted image display device in accordancewith the embodiment;

FIG. 8 is a partly enlarged longitudinal sectional view showing thestructures of the LCD frame and a main prism included in thehead-mounted image display device in accordance with the embodiment;

FIG. 9 is a partly enlarged sectional plan view showing the structuresof a rocking mechanism and a sliding mechanism which are incorporated inan arm included in the head-mounted image display device in accordancewith the embodiment;

FIG. 10 is an exploded perspective view showing a structure that fixes amain prism and a see-through prism which are included in the embodiment;

FIG. 11 shows the structure of an electric circuit board incorporated inthe head-mounted image display device in accordance with the embodiment;

FIG. 12, FIG. 13, and FIG. 14 are longitudinal views showing examples ofthe structure of an elastic member which is detachably attached to themain prism included in the embodiment; and

FIG. 15 is a block diagram showing the configuration of the head-mountedimage display device in accordance with the embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described with referenceto the drawings below.

FIG. 1 to FIG. 15 show an embodiment of the present invention.

A head-mounted image display device 1 is worn on the user's head, andenables the user to view an image with one of his/her right and lefteyes. The head-mounted image display device 1 is of a type allowing auser to hear sounds with one of his/her right and left ears.

FIG. 1 shows a state of using the head-mounted image display device 1 inwhich a user can view an image with his/her right eye. The region of theuser's head on which the head-mounted image display device 1 is worn maybe reversed laterally, whereby the head-mounted image display device 1can be used to view an image with the user's left eye. In this case, animage displayed on an LCD that will be described later is rotated 180°so that the image can be optimally viewed with the user's left eye.

The head-mounted image display device 1 consists mainly of a viewer 2,an arm 3, and a headband 4. The viewer 2 incorporates an LCD 13 (seeFIG. 6) that is an image display element for displaying an image sentfrom an image source, for example, a personal computer, and an opticalsystem including a prism. The arm 3 bears the viewer 2 so that theviewer 2 can pivot, and has a main circuit board 20, which will bedescribed later, incorporated therein. The headband 4 is used to wearthe arm 3 on the head with a plurality of pads between them. At thistime, the arm 3 is held to be able to rock and slide freely.

The viewer 2 consists mainly of an LCD frame 5 and a main prism assembly6.

The LCD frame 5 has the reflective LCD 13, an LCD substrate 14, an LCDdrive circuit substrate 15, LEDs 16, an LED substrate 17, and anillumination prism 28 incorporated in a frame 10. The frame 10 is aframe member made of a metal material that does not transmit light andthat is less susceptible to a change in temperature or humidity. Theframe 10 is substantially sealed to be waterproof and dustproof or tocope with electromagnetic waves or dissipated heat. The LCD substrate 14is an electric circuit board for a display element on which the LCD 13is mounted. The LCD drive circuit substrate 15 mounts a drive circuitfor driving the LCD 13. The LEDS 16 serve as an illuminating member fortime-sequentially irradiating illumination light rays of red, green, andblue to the reflective LCD 13. The LEDs 16 are mounted on the LEDsubstrate 17 that is an electric circuit board for illumination. Theillumination prism 28 conducts light, which is emanated from the LED 16,to the LCD 13.

The LCD frame 5 has the illumination prism 28, LCD substrate 14, and LCDdrive circuit substrate 15 fixed in a first frame 11. The first frame 11has a transparent window 31 or a diffraction optical element fixed in awindow frame 11 a. Thereafter, a second frame 12 is integrated with thefirst frame, whereby the substantially sealed frame 10 is constructed.Thus, the frame 10 consists of the first frame 11 and second frame 12.

FIG. 11 shows the arrangement of the electric circuit boards in thehead-mounted image display device 1. Specifically, an image processingcircuit for reversing an image and a control circuit or the like forextending control according to a operation performed on any of aplurality of switches 26 are mounted on two rigid circuit boards 21 and22. The rigid circuit boards 21 and 22 are linked by a flexibleprinted-circuit board 23, thus constructing the main circuit board 20.The LCD drive circuit substrate 15 is connected to the main circuitboard 20 with a flexible printed-circuit board 24 between them. The LCDsubstrate 14 is connected closely to the LCD drive circuit substrate 15with a flexible printed-circuit board 25 between them. A connector 19 bformed at an end of a flexible printed-circuit board 19 is joined with aconnector receptacle 14 a formed in the LCD substrate 14. Thus, the LEDsubstrate 17 is connected to the LCD substrate 14. A microphone 18 iscoupled to a branch 19 a of the flexible printed-circuit board 19.

The LCD drive circuit substrate 15 and LCD substrate 14 are placed inthe LCD frame 5 with the main surfaces thereof placed substantiallyperpendicularly to each other. The substrates 14 and 15 are, as shown inFIG. 6 and FIG. 7, placed mutually closely. This is because since theLCD 13 is driven with a relatively high-frequency signal, the LCDsubstrate 14 is placed closely to the LCD drive circuit substrate 15 inefforts to minimize radiated noise.

The microphone 18 is incorporated in a microphone attaching member 10 athat is located near the arm 3 at vertically almost the middle of theLCD frame 5 while being embedded in the surface of the frame 10 includedin the LCD frame 5 which faces the user's head. To whichever of theright and left eyes the head-mounted image display device 1 is disposedfor use, the microphone 18 is located at either of laterally symmetricpositions and separated by the same distance from the user's mouth.Consequently, the microphone 18 can collect voice nearly in the samestate.

Consequently, the microphone 18 will not be separately extended from thearm 3 or the like. The head-mounted image display device can thereforebe worn comfortably and can input voice despite the simpleconfiguration. Furthermore, to whichever of the right and left eyes thehead-mounted image display device is disposed for use, the head-mountedimage display device is located nearly at the same position relative tothe right or left eye. This means that the quality of input voice can bestabilized.

The LED substrate 17 has, as shown in FIG. 11, a light passage hole 17 aformed in the center thereof. A pair of LEDs 16 is placed at the bothsides of the light passage hole 17 a. As shown in FIG. 8, the pair ofLEDs 16 is placed on a diffusing/reflecting surface 11 c formed in aroof-shaped convex part 11 b of the first frame 11. The roof-shapedconvex part 11 b may be fixed to the frame member.

Consequently, illumination light radiated from the LEDs 16 ishomogenized and reflected by the diffusing/reflecting surface 11 c.Thereafter, the light falls on the illumination prism 28, which is madeby bonding two triangular prisms 28 a and 28 b, through the lightpassage hole 17 a.

Moreover, another diffusing member may be embedded in the light passagehole 17 a in order to further improve the homogeneity of illuminationlight.

The illumination light falling on the illumination prism 28 is emittedfrom a surface 28 e thereof facing the LCD after being reflected from afirst reflecting surface 28 c and second reflecting surface 28 dthereof. Consequently, the reflective LCD 13 is illuminated.

The LCD 13 reflects light rays of red, green, and blue, which areirradiated sequentially, while controlling the reflectance of each pixellocation. Light reflected from the LCD 13 falls on the surface 28 e ofthe illumination prism 28 facing the LCD. The light is then transmittedby the second reflecting surface 28 d of the illumination prism 28 andemitted from an emitting surface 28 f thereof. The light falls on themain prism assembly 6 through the transparent window 31. The transparentwindow 31 is fixed in the window frame 11 a formed in the frame 10 whilebeing sealed up.

The main prism assembly 6 consists of a main prism 32 and a see-throughprism 33. The main prism 32 that is a member of an optical systemreceives light from the LCD frame 5, and reflects the light from a firstreflecting surface 32 a and a second reflecting surface 32 b thereof.Thereafter, the light is emitted from the first reflecting surface 32 a,and conducted to a user's eye through an eyepiece window 6 a. Thesee-through prism 33 is bonded to the second reflecting surface 32 b ofthe main prism 32. The see-through prism 33 is another member of theoptical system for propagating extraneous light, which comes through anextraneous light incidence window 6 b, to the user's eye.

Protective covers 34 and 35 having a barcode inscribed on at least outersurfaces thereof are placed on the eyepiece window 6 a and theextraneous light incidence window 6 b of the main prism assembly 6,whereby the main prism assembly 6 is kept watertight. Thus, thehead-mounted image display device can cope with various use environmentsincluding the outdoors. The protective covers 34 and 35 may be subjectedto water repellent finishing and thus made waterproof. Otherwise, theprotective covers 34 and 35 may be coated in order to prevent reflectionor to cut ultraviolet rays. Moreover, the protective covers 34 and 35may be made detachable so that when they get dirty or are damaged, theycan be replaced with new ones.

The main prism 32 and see-through prism 33 have, as mentioned above, thesurfaces thereof bonded to each other, and are thus integrated with eachother. As shown in FIG. 10, the main prism 32 has a pair of a firstconcave part 32 c for positioning and a second concave part 32 d forpositioning formed on each of the upper and lower surfaces thereof. Thesecond concave part 32 d has a projection 32 e.

The main prism 32 and see-through prism 33 are fixed in the frame 10included in the LCD frame 5 with a sheet metal member 36 between them.The main prism 32 alone is fixed in the sheet metal member 36. Thesee-through prism 33 is merely secured by utilizing the bonding(strength) to the main prism 32.

The sheet metal member 36 is, as shown in FIG. 10, shaped tosubstantially cover the upper and lower surfaces of the main prism 32.The sheet metal member 36 has two pairs of bends 36 c and 36 d formed asparts of the upper and lower surfaces thereof. The bends 36 c and 36 dhelp positioning the main prism 32 by pressing the first convex parts 32c and second convex parts 32 d onto parts of the frame 10 which thefirst and second convex parts contact.

The sheet metal member 36 has a window 36 a and screw holes 36 b. Lightcoming from the LCD frame 5 passes through the window 36 a. A screw isinserted into each of the screw holes 36 b in order to fix the sheetmetal member 36 to the frame 10 of the LCD frame 5.

The frame 10 has, as mentioned above, the first frame 11 and secondframe 12 joined so that the frame 10 will be substantially sealed. Thefirst frame 11 is, as shown in FIG. 10, realized with a substantiallybox-like member having the window frame 11 a. The first frame 11 hasscrew holes 11 h bored to coincide with the screw holes 36 b of thesheet metal member 36. Moreover, the first frame 11 has rectangularconvex parts 11 i, end surfaces 11 f, end surfaces 11 g, and concaveparts lie. Each of the rectangular convex parts 11 i is inserted into aspace between each of the two pairs of bends 36 c and 36 d, thus helpingposition the first frame 11. Each of the end surfaces 11 f contacts thefirst convex part 32 c of the main prism 32, thus helping position thefirst frame 11. Each of the end surfaces 11 g contacts the second convexpart 32 d of the main prism 32, thus helping position the first frame11. Each of the concave parts lie is engaged with the projection 32 eformed on the second convex part 32 d, thus helping position the firstframe 11.

Owing to the foregoing structure, in order to construct the main prismassembly 6, the sheet metal member 36 is attached to the main prism 32so that the first and second convex parts 32 c and 32 d of the mainprism 32 will be contacted to the bends 36 c and 36 d of the sheet metalmember 36. The first frame 11 is externally-mounted on the sheet metalmember 36. The projection 32 e of the second convex part 32 d of themain prism 32 is fitted into the concave part 11 e of the first frame11. Each of the first and second convex parts 32 c and 32 d is thensandwiched between the bends 36 c and 36 d of the sheet metal member 36and the end surfaces 11 f and 11 g of the first frame 11.

Consequently, the main prism 32 has the upper and lower surfaces thereofclamped by the sheet metal member 36, and is thus vertically positioned.Moreover, the main prism 32 has the first and second convex partsthereof sandwiched between the bends 36 c and 36 d of the sheet metalmember 36 and the end surfaces 11 f and 11 g of the first frame, and isthus positioned in one direction. Moreover, the projection 32 e of thesecond convex part 32 d is fitted into the concave part 11 e of the endsurface 11 g of the first frame, whereby the main prism 32 is positionedin a direction orthogonal to the one direction. Consequently, thespatial arrangement of the main prism is perfectly determined.

Thereafter, screws are inserted into screw holes 11 h of the first frame11 and the screw holes 36 b of the sheet metal member 36, and thentightened. Consequently, the sheet metal member 36 and first frame 11are integrated with each other.

As mentioned above, one prism alone is fixed, and the other prism isheld by utilizing bonding (strength). Consequently, stress applied tothe prisms can be lightened to the greatest extent, and a damage causedby resistive strain can be prevented. The sheet metal member 36 isattached to the portion of the main prism that is engaged with the sheetmetal member 36. Any screw is not directly inserted into the main prism.Consequently, strain or damage of the prisms can be prevented.

The outer surface of the main prism assembly 6 is covered with anelastic member 38 that is detachable. The elastic member 38 serves as asupporting member and is made of, for example, an elastomer. The elasticmember 38 has rectangular holes formed to coincide with the eyepiecewindow 6 a and extraneous light incidence window 6 b. Light passesthrough the rectangular holes. A nose rest 38 a that contacts a regionin which the nasal bone lies subcutaneously close to the skin isprojected as shown in FIG. 1 and FIG. 2.

The elastic member 38 may be fixed to the outer surface of the mainprism assembly 6.

A portion of the elastic member 38 for supporting the main prismassembly 6 at a predetermined position in front of a user's eye is notlimited to the nose rest 38 a. For example, as shown in FIG. 12, aportion 38 b may be formed so that it will contact a region in which abone lies subcutaneously close to the skin. Otherwise, as shown in FIG.13, a portion 32 c may be formed so that it will contact a region inwhich the superior ocular bone lies subcutaneously close to the skin.

As mentioned above, the head-mounted image display device 1 isstructured so that it will contact a region of the head in which a bonelies subcutaneously close to the skin. Consequently, even if the mainprism assembly 6 is pressed abruptly, a user's eye is protected frombeing pressured. Moreover, the head-mounted image display device 1 canbe held on a stable basis.

The elastic member 38 may be made available in a plurality of kinds inassociation with use forms. Otherwise, as shown in FIG. 14, a portion 38d may be formed along the perimeter of the main prism assembly 6 inorder to block the gap between the perimeter thereof and a user's eye.

In this case, extraneous light that enters through the see-through prismcan be intercepted. An image can be clearly viewed on a stable basisirrespective of an indoor or outdoor environment. Furthermore, thedistance between a user's eye and the main prism assembly 6 (or avirtual image) can be held nearly constant.

Moreover, the elastic member 38 may be formed to extend along the outerframe of a lens of spectacles. In this case, the head-mounted imagedisplay device can be adapted to a user who wears spectacles. Needlessto say, a user who does not wear spectacles would find the head-mountedimage display device, which has this kind of elastic member 38, morecomfortably fit.

Furthermore, the elastic member 38 may be made available in two kinds.One kind of elastic member 38 has a window coincident with theextraneous light incidence window of the prism assembly, and the otherkind of elastic member 38 intercepts light coming through the extraneouslight incidence window. In this case, a special extraneous light shutoutmechanism need not be included. Nevertheless, a mode in which an LCDimage is superimposed on an image represented by extraneous light and amode in which an LCD image alone is viewed can be used selectively.

In other words, in the mode in which an LCD image is superimposed on animage represented by extraneous light, a scene 42 represented byextraneous light is, as shown in FIG. 5, superimposed on an image 43produced by the LCD 13. In the mode in which an LCD image alone isviewed, the scene represented by extraneous light is intercepted, andthe LCD image can therefore be viewed more clearly.

The aforesaid viewer 2 is borne by the arm 3 so that it can pivot on ahinge 45.

The aforesaid main circuit board 20 is incorporated in the arm 3. Themain circuit board 20 is formed by linking the two rigid circuit boards21 and 22 using the flexible printed-circuit board 23. Consequently,despite the use of the rigid circuit boards, the arm 3 that isstreamlined in conformity with the shape of the user's head can bedesigned to be thin.

The arm 3 is supported so that the position thereof can be adjustedusing a rocking mechanism, which is realized with a ball joint, and asliding mechanism that is realized with a sliding member and a slidinggroove. The rocking mechanism and sliding mechanism will be describedwith reference to FIG. 9.

The headband 4 includes right and left face pads 46 and 47 and a centralhead pad 48. The arm 3 is coupled to the face pad 46.

The face pad 46 consists mainly of a pad 51 that comes into contact withthe head and a pad frame 52 that bears the pad 51. A housing frame 53having a concave curved portion 53 a is engaged with the pad frame 52.

A shaft member 55 having a ball 54 fixed to the distal end thereof isfixed to the housing frame 53 with a washer 56 and a nut 57 betweenthem. The shaft member 55 is extended from the bottom of the concavecurved portion 53 a.

A sliding groove 61 is formed in a portion of the arm 3 facing theuser's head. A sliding member 62 is engaged with the sliding groove 61so that it can slide freely in the longitudinal direction of the arm 3.

A bowl-shaped convex part 62 a that projects towards the user's head isformed in the middle of the sliding member 62. The bowl-shaped convexpart 62 a juts out of a sliding window 61 a that is formed to open ontothe sliding groove 61.

The bowl-shaped convex part 62 a has a through hole 62 b bored in thedistal end thereof, and has a ball bearing 63, which bears the ball 54,fixed therein.

The ball bearing 63 consists of a lower ball bearing member 63 a and anupper ball bearing member 63 b. In order to assemble the lower and upperball bearing members, the lower ball bearing member 63 a is first put inthe bowl-shaped convex part 62 a. Thereafter, the shaft member 55 ispassed through the through hole 62 b of the bowl-shaped convex part 62a. The ball 54 is fixed to the distal end of the shaft member 55 using ascrew or the like. The upper ball bearing member 63 b is then placed onthe ball 54. A screw 64 or the like is then inserted into the upper andlower ball bearing members Thus, the ball bearing 63 is fixed to thesliding member 62.

As mentioned above, three position adjusting mechanisms are included forenabling adjustment of the position of the viewer 2 relative to a user'seye. Consequently, as shown in FIG. 3 and FIG. 4, the viewer 2 canfreely pivot on the hinge 45. Moreover, the length by which the arm 3extends forward relative to the headband 4 can be freely adjusted usingthe sliding mechanism, and the degree of rocking of the arm 3 in anydirection around the ball 54 can be freely adjusted using the rockingmechanism.

The viewer 2 can be freely adjusted so that it will be separated fromthe user's eye by any distance or it will meet the arm 3 at any angle.Consequently, the head-mounted image display device can be worn by alarge number of users who are different from one another in terms of thesize of the head and the position of an eye, so that it will be locatedat a desired most easy-to-see position on any user′ head.

Three position adjusting mechanisms are included. The number of positionadjusting mechanisms may be varied depending on the degree of necessityof adjustment. Alternatively, two position adjusting mechanisms will do.Otherwise, needless to say, a larger number of adjusting mechanisms maybe included.

On the other hand, the plurality of switches 26 mounted on the maincircuit board 20 are turned on or off by pressing button members 65 thatare exposed on the outer surface of the arm 3 and that are connected tothe switches 26.

A main cable 66 over which a video signal and an audio signal aretransmitted is extended from the rear end of the arm 3, and routed to animage/voice source such as a personal computer. An earphone cable 67 isextended from the rear end of the arm 3, and an earphone 68 is attachedto the distal end of the earphone cable 67. The earphone 68 is of amonophonic type that enables one of the user's ears to hear sounds, sothat external sounds can be heard with the other ear. A digitalinterface for liquid crystal displays (for example, a digital interfacein compliance with the TMDS, LVDS, or GVIF) or an analog RGB interfaceis used to connect the head-mounted image display device to a personalcomputer.

An earphone mount 69 is formed, close to a user's ear, on the surface ofthe rear portion of the arm 3 that faces an ear. The earphone 68 ismounted in the earphone mount 69 with a sound generating portion thereoforiented inwards.

Consequently, a user may dismount the earphone 68 from the earphonemount 69 and insert it into his/her ear for use. Otherwise, the user mayhear sounds with the earphone 68 held mounted in the earphone mount 69.

A graphic controller 121 is incorporated in a wearable PC 120 or thelike, the details of which are not shown, in order to control display ofthe viewer. Interface circuits 122 and 125 are circuits for transmittingor receiving a high-definition motion picture that expresses a grayscale using 24 bits and complies with the VGA, SVGA, or XGA. Thewearable PC 120 has a connector 123, and the viewer has a connector 124.The connectors 123 and 124 are linked by an interface cable 129 thatacts as a bus.

The viewer has the interface circuit 125, an LCD controller 15, the LCD13, the LED drive circuit 128, a microprocessor unit (MPU) 126, and areprogrammable memory 127. The interface circuit 125 transfers data toor from the PC 120. The LCD controller 15 receives data that isconverted from serial data to parallel data by the circuit 125, andcontrols display of an image on the LCD 13. The LCD 13 displays an imageon the LCD 13 under the control of the LCD controller 15. The LED drivecircuit 128 drives the LEDs 16 in response to an LED control signal sentfrom the LCD 13. The MPU 126 controls the whole viewer. Thereprogrammable memory 127 stores firmware for controlling display of animage on the viewer.

Due to the control of display extended from the graphic controller 121incorporated in the PC, the interface circuit 122 converts parallel datainto serial data. The display data is received by the interface circuit125 incorporated in the viewer over the interface cable 129. Theinterface circuit 125 converts the serial data into parallel data, andtransmits the display data to the LCD controller 15.

Initial data concerning the MPU 126, LCD controller 15, and LCD 13,user-specified data including a luminance and the contrast of an image,and information necessary to control display are stored in thereprogrammable memory 127. The reprogrammable memory 127 that isreprogrammable is realized with, for example, an EPROM, an EEPROM, or aflash memory. The reprogrammable memory 127 may be reprogrammed throughan operating interface with the cover of the viewer opened. Otherwise, amemory module realizing the reprogrammable memory 127 may be replacedwith a memory module with a receptacle. Thus, firmware for controllingdisplay can be updated. The cover of the viewer may not be opened inorder to pass control from the PC 120, but an initial program loader(IPL) residing in the memory 127 may be activated using an installprogram, whereby the reprogrammable memory 127 may be reprogrammed.

In the example shown in FIG. 15, the reprogrammable memory 127 isseparated from the MPU 126. Alternatively, the memory 127 may beincorporated in the MPU 126.

This simplifies addition or modification of any feature or bug patches.The viewer which has the reflective LCD and in which the reprogrammablememory 127 can be updated has been described so far. The viewer may beadapted to a spectacles-type head-mounted image display device(transmissive LCD) that the present applicant has already proposed inJapanese Patent Application No. 11-177253.

The headband 4 has the right and left face pads 46 and 47 and thecentral head pad 48 attached to a sheet metal member 49 that is elasticand shaped substantially like an arc. As mentioned above, the face pad46 is coupled to the arm 3 with a ball joint between them.

The headband 4 is worn on the head over the occipital region between thetemporal regions. The headband 4 is held on the head due to theelasticity of the sheet metal member 49. However, how the headband isworn on the user's head is not limited to the above method. For example,the headband may be worn over the parietal region between the temporalregions.

Moreover, when a user wants to view an image with his/her left eye, theworn state of the head-mounted image display device shown in FIG. 2 isreversed 180°. Namely, the head-mounted image display device is worn onthe left region of the head. The button member 65 is operated in orderto rotate 180° an image displayed on the LCD 13 so that the image to beviewed will be displayed at a proper position. An image rotating meansfor rotating an image is realized by the electric circuit boards shownin FIG. 11. As a variant, a signal produced responsively to a operationperformed on the button member 65 may be sent to a personal computer orthe like (not shown). An image may then be rotated in the personalcomputer, and viewed on the head-mounted image display device.

The personal computer is not limited to a notebook type personalcomputer or a desktop personal computer but may be a portable personalcomputer or a wearable personal computer.

In the aforesaid viewer 2, the LCD 13, LED substrate 17, LCD drivecircuit, and illumination prism 28 are put in the frame 10 that issubstantially sealed. Alternatively, these components may not be put inthe sealed structure, but the LCD 13 and LED substrate 17 alone may beput therein or the LCD 13, LED substrate 17, and LCD drive circuit maybe put therein. Whichever of the components are put in the frame 10 thatis substantially sealed may be determined according to the arrangementof circuit boards or the required degree of waterproofness ordustproofness.

According to the present embodiment, more than two position adjustingmechanisms are included for enabling adjustment of the position of theviewer relative to a user's eye. Therefore, at whatever position theheadband is worn in order to cope with a difference of a user fromanother individual, the head-mounted image display device can bepositioned at an optimal position for image display.

Moreover, the LED substrate and microphone are connected through aconnector. This simplifies maintenance and repair of a failure.

One of two prisms that are bonded to each other in order to construct anoptical system is fixed in the frame, and the other prism is held byutilizing the bonding (strength). The strain or damage of a prism can beavoided. Furthermore, the prism is fixed in the frame while being merelyclamped by the sheet metal member. Consequently, the strain or damage ofa prism can be prevented more reliably.

Furthermore, illumination light emanating from the LEDs is conducted tothe reflective LCD via the illumination prism. Compared with whenillumination light is conducted directly to the reflective LCD, thehead-mounted image display device can be manufactured as a more compactproduct.

Light emanating from the LEDs is temporarily reflected from thediffusing/reflecting surface formed in the frame in order to be thushomogenized. Thereafter, the light is irradiated to the LCD. Despite thesimple structure, therefore, irregular emission of light from the LEDscan be coped with and a loss in light can be prevented. Moreover, as avariant, light emanating from the LEDs may be conducted directly to theillumination prism, and the diffusing/reflecting surface is formed inthe illumination prism. Nevertheless, the variant can provide the sameadvantages as the present embodiment.

Moreover, the frame is made of a metal or any other material that doesnot transmit light. Leakage of light emanating from the LEDs thereforecan be prevented and the light can be reflected at a high reflectance.Consequently, a high luminance can be ensured. In addition, the adoptionof a metal facilitates heat dissipation.

The outer surface of the main prism is covered with an elastic membermade of an elastomer or the like. Moreover, the nose rest that contactsa region in which the nasal bone lies subcutaneously close to the skinis formed with the elastic member. The nose rest can therefore deform inconformity with the shape of a region which the nose rest contacts, andabsorb extraneous force. This results in improved comfort in wearing thehead-mounted image display device.

The elastic member is attachable and detachable. Therefore, even whenthe same head-mounted image display device is worn by a plurality ofusers, if the elastic member is renewed for each user, the head-mountedimage display device can be kept sanitary. Moreover, even if the elasticmember must be replaced with a new one because it is damaged or soiled,the elastic member can be renewed readily. Various elastic members ofdifferent shapes may be made available. In this case, the head-mountedimage display device can be flexibly worn by users who have individualdifferences or in different use forms.

The present invention is not limited to the aforesaid embodiment.Needless to say, various modifications and applications can be achievedwithout a departure from the gist of the invention.

Industrial Applicability

According to the present invention, there is provided a compactcomfortably-wearable head-mounted image display device. Herein, since amicrophone is mounted in a frame member, the microphone will not beextended using a separate arm member or the like.

Moreover, whether the head-mounted image display device is disposedopposite the user's right eye or left eye, the user's mouth and themicrophone have nearly the same positional relationship, though themicrophone is located on the right or left side of the user's mouth.Voice can therefore be collected without the necessity of causing theuser to feel that something is wrong.

Furthermore, a supporting member is used to place a viewer so that theviewer will have a predetermined positional relationship to the user'seye. The viewer will therefore not be displaced, and the user can viewan image on a stable basis. The head-mounted image display device isthus compact and comfortably wearable.

The supporting member is made of an elastic material. This leads toimproved comfort in wearing the head-mounted image display device. Evenif extraneous force is applied unexpectedly, the influence of theextraneous force can be alleviated.

In addition, the supporting member is contacted a region in which atleast one of the nasal bone, cheekbone, and superior ocular bone liessubcutaneously close to the skin. Even if extraneous force is appliedunexpectedly, the user's eye can be protected reliably.

Furthermore, the supporting member is formed along the perimeter of theviewer in order to block the gap between the viewer and user's eye. Thisenables the user to view an image on a stable basis while beingunaffected by an ambient environment. Moreover, the viewer will not lievery closely to the user's eye.

The supporting member has a portion that covers an optical system. Theoptical system can therefore be protected. Moreover, the supportingmember is attachable or detachable. Even if the head-mounted imagedisplay device is worn by a plurality of users, it can be kept sanitary.When the supporting member is shaped to cope with a difference of a userfrom another individual, the user can wear the head-mounted imagedisplay device more comfortably.

An electric circuit board for a display element and an electric circuitboard for illumination are connected to each other through a connector.The circuit boards can therefore be separated from each other for thepurpose of maintenance or repair of a failure.

Furthermore, the electric circuit board for illumination is held on adiffusing/reflecting surface of a frame member. This enablesillumination of homogeneous light without causing irregular emission oflight.

In addition, the frame member bears an image display element so that theimage display element will be at least substantially sealed.Consequently, the viewer is substantially sealed. The head-mounted imagedisplay device is therefore kept waterproof or dustproof even when usedoutdoors.

What is claimed is:
 1. A head-mounted image display device having aviewer located in front of a user's eye to make an image viewablewherein: said viewer comprises: an image display element, an opticalsystem for forming an image, said image being displayed on said imagedisplay element allowing said image to be viewed, and a frame member forbearing said image display element at a predetermined position relativeto said optical, system; said head-mounted image display device furthercomprising: an electric circuit board for a display element on whichsaid image display element is mounted, an illuminating member forilluminating said image display element, an electric circuit board forillumination on which said illuminating member is mounted, and aconnector through which said electric circuit board for a displayelement and said electric circuit board for illumination are connectedand disconnected from each other; wherein said electric circuit boardfor illumination is held in at least one of said frame member and anilluminating member-fixing member that is fixed in said frame member,and; a surface of a portion of said frame member of illuminatingmember-fixing member that holds said electric circuit board forillumination is formed as a diffusing/reflecting surface thathomogenizes and reflects light emanating from said illuminating member.2. A head-mounted image display device of a monocular type, comprising,a viewer having an image display element; an optical system for formingan image displayed on said image display element so that said image canbe viewed; a frame member for bearing said image display element so thatsaid image display element will be located at a predetermined positionrelative to said optical system; an arm which bears said viewer so thatan eyepiece window of said viewer may be located in front of one of auser's right and left eyes; and a support member which is used to wearsaid arm on a user's head; wherein a region of said user's head on whichsaid support member is worn may be reversed laterally as said user maywish such that said eyepiece window of said viewer may be located infront of the other of said user's right and left eyes with which saiduser is allowed to view said image.
 3. The head-mounted image displaydevice according to claim 2, wherein: said arm and said support memberare joined using a rotatable joint mechanism.
 4. The head-mounted imagedisplay device according to claim 3, further comprising: at least onecircuit board for said image which is to be displayed on said imagedisplay element, said image being rotated 180° at least one ofvertically and laterally.
 5. The head-mounted image display deviceaccording to claim 4, wherein: a microphone is provided in said framemember.
 6. The head-mounted image display device according to claim 2,further comprising: at least one circuit board for said image which isto be displayed on said image display element, said image being rotated180° at least one of vertically and laterally.
 7. The head-mounted imagedisplay device according to claim 6, wherein: a microphone is providedin said frame member.